Impact of donor-specific anti-HLA antibodies and donor KIR characteristics in haploidentical HSCT for beta-Thalassemia

In the present study we investigated the role of donor specific HLA antibodies (DSA) and donor KIR repertoire characteristics in a group of 18 patients affected by haemoglobinopathies who underwent haploidentical T cell depleted transplantation. Among these patients, 8 rejected the transplant while 10 had complete donor chimerism (CC). Five out of 8 patients (62.5%) who rejected graft had anti-HLA antibodies in the sera collected before transplant, while only 1 patient out of 10 (10%) with CC showed their presence (p=0,042). Notably, of the 5 HLA antibodies positive patients who rejected the graft 3 had DSA (2 for class I and 1 for class I and II) while none of the patients with CC had DSA. Among the 8 patients that experienced graft failure 4 were transplanted with a donor characterized by the lack of NK alloreactivity and 5 with a donor with a B content value <2. Although we analyzed a small cohort of patients, our data indicated that the presence of anti-HLA antibodies in patient sera, but not donor KIR characteristics, correlates with graft failure thus suggesting that analysis of anti-HLA antibodies should be taken into account in haploidentical transplant setting.